Numerically controlled swiss machine is affected by the change of workshop environment temperature, motor heating and mechanical movement friction heating, cutting heat and cooling medium, resulting in uneven temperature rise of each part of the machine tool, leading to changes in the machine tool shape accuracy and machining accuracy.
For example, if a 70mm×1650mm screw is machined on an ordinary precision CNC lathe, the workpiece milled from 7:30 to 9:00 in the morning is compared with the workpiece processed from 2:00 to 3:30 in the afternoon, and the cumulative error varies up to 85m. Under constant temperature conditions, the error can be reduced to 40m.
For another example, a precision double-end grinding machine for double-end grinding of thin steel sheet workpieces with a thickness of 0.6～3.5mm can reach the dimensional accuracy of mm when processing 200mm×25mm×1.08mm steel sheet workpieces at the time of acceptance. The total length is less than 5m. But after 1h of continuous automatic grinding, the size change range increased to 12m, and the coolant temperature rose from 17°C at startup to 45°C. Due to the influence of grinding heat, the spindle journal is elongated and the clearance of the front bearing of the spindle increases. Accordingly, adding a 5.5kW refrigerator to the machine tool coolant tank has an ideal effect.
Practice has proved that the deformation of the CNC swiss machine after heating is an important reason that affects the machining accuracy. However, the machine tool is in an environment where the temperature changes anytime and anywhere; the core-type CNC lathe itself will consume energy when it is working, and a considerable part of this energy will be converted into heat in various ways, causing physical changes in the various components of the machine tool. This kind of change is different because of the different structure, material difference and other reasons. The designer of cnc machine tools should master the heat formation mechanism and temperature distribution law, and take corresponding measures to minimize the impact of thermal deformation on machining accuracy.
Link to this article: The Effect Factor Of CNC Swiss Machine Accuracy